Lemma A.2 (Chernoff bound [1]}) 

Let \(X = \sum _{i =1}^n X_i\) , where \(X_i = 1\)  with probability \(p_i\)  and \(X_i = 0\)  with probability \(1 - p_i\) , and all \(X_i\)  are independent. Let \(\mu = \operatornamewithlimits{{\mathbb {E}}}[X] = \sum _{i = 1}^n p_i\) . Then
